DEBIAN-CVE-2026-40864
JupyterHub is software that allows users to create a multi-user server for Jupyter notebooks. In versions 4.1.0 through 5.4.4, XSRF protection (updated in 4.1.0) inappropriately treated requests with Sec-Fetch-Mode: no-cors as same-origin requests, bypassing XSRF checks. The JSON API is not affected, only HTTP form endpoints, such as /hub/spawn and /hub/accept-share, meaning attackers could trigger server spawn (but not access the server) and if the attacker is a JupyterHub user permitted to share access to their server, cause a user to accept a share and have access to the attacker's server. This issue has been fixed in version 5.4.5. If developers are unable to immediately upgrade, they can temporarily mitigate this issue by dropping requests to JupyterHub with Sec-Fetch-Mode: no-cors if they are using a reverse proxy.
DEBIAN-CVE-2026-40864
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:DEBIAN-CVE-2026-40864
jupyterhub
Source reference: /affected/0/package/name
- Affected versions
- 5.2.1+ds1-4
Source reference:
/affected/0/versions5.2.1+ds1-5Source reference:
/affected/0/versions - Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
jupyterhub
Source reference: /affected/1/package/name
- Affected versions
- 5.2.1+ds1-4
Source reference:
/affected/1/versions5.2.1+ds1-5Source reference:
/affected/1/versions - Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "jupyterhub",
"purl": "pkg:deb/debian/jupyterhub?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"5.2.1+ds1-4",
"5.2.1+ds1-5"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40864.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "jupyterhub",
"purl": "pkg:deb/debian/jupyterhub?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"5.2.1+ds1-4",
"5.2.1+ds1-5"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-40864.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
]Publisher severity
No explicit severity was provided.
- Event
- #56478 · Revision 1
- Added to Heist Feed
- Publisher date